They found that adolescents with BD had significantly higher spontaneous levels of NF-κB in peripheral blood mononuclear cells, monocyte and lymphocyte populations, and higher plasma levels of interleukin-1β (IL-1β) than healthy youth, while any inflammatory cytokine levels were not significantly altered in youth with MDD compared to either the BD or HC groups. This evidence concerns the gene IL1B and major depressive disorder.